P1697: CHARACTERISTICS, TREATMENT PATTERNS AND HEALTHCARE UTILIZATION OF PATIENTS WITH WARM AUTOIMMUNE HEMOLYTIC ANEMIA INITIATING FIRST LINE THERAPY OF ORAL CORTICOSTEROIDS WITH OR WITHOUT RITUXIMAB
Authors: Irina Murakhovskaya, Concetta Crivera, Ann Leon, Evo Alemao, Vamshi Ruthwik Anupindi, Mitch Dekoven, Victoria Divino, Iris Lin, Cathye Shu, Tarek Ebrahim
Journal: HemaSphere (2023)

Topic: 36. Ethics and health economics Background: Warm autoimmune hemolytic anemia (wAIHA) is a rare life-threatening disorder caused by autoantibodies that lead to the premature destruction of healthy red blood cells. Due to a paucity of clinical trials and no approved treatment, the First International Consensus meeting published recommendations in 2020 with goals to provide international guidelines for diagnosis and to create a framework for current treatment of autoimmune hemolytic anemia (AIHA). Oral corticosteroids (OCS) remain as first-line (1L) therapy for wAIHA, while the addition of rituximab (R) in 1L was recommended only in select patients due to limited duration of follow up and power in prospective studies evaluating the effect of 1L OCS plus rituximab (OCS+R) on the need for other treatments or inducing long-term remission. Experts highlighted the limited evidence base and recommended that clinicians should consider discussion of available clinical trials at all stages of treatment. Aims: This study described real-world treatment patterns and healthcare resource utilization (HCRU) of patients with wAIHA initiating 1L OCS+R compared to 1L OCS. Methods: A retrospective cohort study was conducted using IQVIA pharmacy and medical claims databases in the US to identify patients with a diagnosis code for wAIHA (D59.11) from 8/2020-3/2022. Patients initiating 1L OCS +/- R were identified (date of initiation = the ‘index date’) and required to have a 1-year pre-index (baseline) period and a minimum 1-year post-index (follow-up) period. Baseline clinical and demographic characteristics were collected. Treatment and utilization patterns were reported over the follow-up. Data were analysed using descriptive statistics. Study outcomes for the 1L OCS+R and 1L OCS cohorts were reported as a composite for primary and secondary wAIHA. Results: The final sample comprised 77 1L OCS+R patients and 400 1L OCS patients (~60% female and mean age >64 years). The OCS+R cohort had more patients with a hematology/oncology visit associated with the index date compared to the OCS cohort (71.4% and 55.3%, respectively). For both cohorts, hematologic malignancy was the most common associated condition (23.4% OCS+R and 19.0% OCS) followed by solid tumors (18.2% and 14.8%, respectively), and autoimmune disease (7.8% and 11.8%, respectively) (not mutually exclusive). Over the 1-year follow-up, HCRU was higher in the OCS+R cohort with higher mean number of physician office visits (22.9 and 14.4), including hematology/oncology office visits (10.7 and 5.6), and higher utilization of rescue therapy (59.7% and 33.3%), driven by higher use of injectable corticosteroids (50.6% and 24.8%). Use of outpatient red blood cell transfusion and inpatient hospitalization was comparable between groups. Patients in OCS+R and OCS groups completed 1L therapy after a similar mean duration of 103.5 and 134.6 days, respectively. In the majority of patients, treatment with OCS + R did not extend the remission period because second-line (2L) therapy was initiated at a similar timepoint: 66.2% OCS+R and 72.0% OCS cohorts initiated 2L in a mean of 218.3 and 203.2 days after the end of 1L treatment, respectively. Summary/Conclusion: Despite the addition of rituximab in 1L, duration of remission was brief in both cohorts with most patients initiating 2L therapy within less than 1 year of completing 1L treatment. In addition, substantial HCRU burden was observed among patients initiating 1L OCS+R. More effective novel therapies targeted to the underlying pathophysiology are needed to address the high unmet need to maintain long-term remission in patients with wAIHA.Keywords: Autoimmune hemolytic anemia (AIHA), Treatment, Health care